Ubuntu 14.04 - cannot connect to wifi. What gives?
April 1, 2016 7:25 PM   Subscribe

I finally upgraded to 14.04 and now, while my laptop can see networks, it is unable to connect to any of them. Other machines on our network have no issues. Please help me troubleshoot this!

I am a Linux n00b - please be gentle with me. Any suggestions are much appreciated.
posted by ryanshepard to Computers & Internet (11 answers total)
 
1. Run lspci in the terminal. Note what wireless card is in your laptop.
2. Google the wireless card plus ubuntu 14.04
3. Hope somebody has posted a easy to follow step by step troubleshooting or work around procedure.
posted by COD at 8:06 PM on April 1, 2016


I'd disagree - if it can see networks, it isn't having any trouble controlling the wireless card.

If it was me, I'd try to figure out what command line to run to connect to the network, then run that in a terminal with "verbose" flags to see what specific errors come up. And perhaps there are relevant log files you could look at.

Or alternatively, you could try to install a different tool for managing the wireless card to see if it will work, though I am usually inclined to first attempt to figure out why what's already installed doesn't work or has stopped working.
posted by XMLicious at 9:19 PM on April 1, 2016


New to Linux? Good time to get acquainted with checking syslog.
posted by Good Brain at 10:07 PM on April 1, 2016


If you get no joy here, I'd suggest checking out the questions and answers at Ubuntu Forums
posted by Mister Bijou at 11:09 PM on April 1, 2016


Just because it can get the names of local access points doesn’t mean that there isn’t a problem elsewhere in the driver that stops it connecting properly. Seeing the list of access points only requires the RX radio path whereas connecting requires correct use of the TX radio.

COD is right. First step is to google the name of your laptop & Ubuntu 14.04 wireless to see if anyone else is seeing the same issues. Next step is to do the lspci thing & Google those details.

Do make sure that your Ubuntu install has all the updates applied first though - it’s possible that the problem has been fixed in a kernel update over the last year. This might require plugging a physical ethernet cable between your laptop on your router or, if your laptop doesn’t have an ethernet port, borrowing a USB wifi or ethernet device from a friend.
posted by pharm at 1:10 AM on April 2, 2016


i'm not sure what you mean by "upgraded" to 14.04? were you running an earlier version before or do you upgraded from windows?

either way, you need to find out what happens when you try to connect to the wireless access point. if you already have a 'profile' for the access point in the network manager, i would delete it and try connecting fresh.

after the connection fails, you need to open a terminal window and type 'less /var/log/syslog'

after scrolling through a lot of stuff you should see a line something like:
Apr 2 10:59:52 computer_name dhclient: DHCPREQUEST of 192.168.1.110 on wlan1 to 192.168.1.1 port 67 (xid=0x300e5c4e)
after this line there should be some kind of error message. google that error message with ubuntu and the name of your wireless card or at least the make and model of your laptop...
posted by ennui.bz at 4:27 PM on April 2, 2016


A little out of left field, I had a similar problem once upon a time, and it turned out the issue was that the network manager applet wasn't showing the popup where you'd go to enter the wifi password.

I never figured out why, but I did discover that if you went into network settings, manually opened the settings for the desired network, and added the password there, under the security tab, that solved my problem.

Worth a try, anyhow.
posted by sunimplodes at 5:17 PM on April 2, 2016


Nm-applet is horribly buggy in 14.04, I usually have to use nm-cli.
posted by miyabo at 8:38 AM on April 3, 2016


Also, why not try Ubuntu 15.10? I know 14.04 is the LTS release, but it’s fairly long in the tooth at this point.
posted by pharm at 9:26 AM on April 3, 2016


The next LTS release -- 16.04 -- rolls out on 21 April 2016.
posted by Mister Bijou at 10:56 AM on April 3, 2016


If you haven't, try:

1. Restarting the router.

2. Running sudo apt-get update/sudo apt-get upgrade/sudo apt-get dist-upgrade.

3. Logging into the router's web interface--probably 192.168.1.0 or something similar--and releasing the laptop's mac address (I've had conflicts here before).

4. Making sure "iwlist wlan0 scan" shows the networks you're seeing in the applet (may also require sudo privileges, and your card might be named something else, like wlan1).

5. Get hold of a usb wireless card and see if it can connect to the router using that.

In addition to checking the syslog, there are a ton of command-line tools like netstat, ifup, iwconfig, lspci, dmesg that can give you way more information about what's happening, but there's a learning curve. If you go down this particular rabbit hole, this is a great time to learn some more command line tricks like pipes, e.g. lspci | grep Ethernet.

I have absolutely had a network card fail before, so that's a possibility too.
posted by aspersioncast at 12:27 PM on April 3, 2016


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